From dde75313eed0b014c437f48dd75c0308b592cbf9 Mon Sep 17 00:00:00 2001 From: Sergey Senozhatsky Date: Wed, 29 Jul 2026 13:57:35 +0900 Subject: [PATCH] zram: set default primary compressor in zram_destroy_comps() Patch series "zram: fix zram issues reported by sashiko". Sashiko drove by and reported [1] a couple of zram issues: a possible BUG_ON() in zlib code due to missing winbits range validation and one possible NULL-ptr dereference in zcomp. Both are low risk yet still worth fixing. This patch (of 2): zram_destroy_comps() resets all compressors and leaves them set to NULL, including the primary one, which is invalid device state, as now comp_algorithm_show()->strcmp() can be called on a NULL compressor. Set default primary compressor in zram_destroy_comps(). Link: https://lore.kernel.org/20260729045745.775973-2-senozhatsky@chromium.org Fixes: 486fd58af7ac ("zram: don't free statically defined names") Link: https://sashiko.dev/#/patchset/20260728092935.31139-1-haoqinhuang7@gmail.com [1] Signed-off-by: Sergey Senozhatsky Cc: Minchan Kim Cc: Haoqin Huang Cc: Signed-off-by: Andrew Morton --- drivers/block/zram/zram_drv.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c index 4bfe63a5225d..cfa98846ac48 100644 --- a/drivers/block/zram/zram_drv.c +++ b/drivers/block/zram/zram_drv.c @@ -2828,6 +2828,7 @@ static void zram_destroy_comps(struct zram *zram) zram->comp_algs[prio] = NULL; zram_comp_params_reset(zram); + comp_algorithm_set(zram, ZRAM_PRIMARY_COMP, default_compressor); } static void zram_reset_device(struct zram *zram) @@ -2845,8 +2846,6 @@ static void zram_reset_device(struct zram *zram) zram_destroy_comps(zram); memset(&zram->stats, 0, sizeof(zram->stats)); reset_bdev(zram); - - comp_algorithm_set(zram, ZRAM_PRIMARY_COMP, default_compressor); } static ssize_t disksize_store(struct device *dev, struct device_attribute *attr,